---
title: "midiHost: a Raspberry Pi MIDI router"
description: "A Raspberry Pi with a small screen that lets a MIDI keyboard play a Novation Circuit or a Korg Kaossilator without a computer."
date: 2019-09-09T12:52:07+02:00
lastmod: 2026-10-16T18:58:52+02:00
url: https://klimek.link/projects/midihost/
author: "Marcin Klimek"
source: https://klimek.link/projects/midihost/
---

# midiHost: a Raspberry Pi MIDI router

**midiHost** turns a **Raspberry Pi 2** with a small PiTFT screen and four buttons into a standalone USB MIDI host, so that my Akai MPK mini Play can play other instruments without a computer in between.

Incoming MIDI events go into a queue on a dispatcher thread and pass through a chain of filters (transpose, channel mapping, controller mapping, pressure to CC) before they're sent on. There are two targets I set it up to talk to:

- A **Novation Circuit** gets notes on channel 1 or 2, one channel per synth.
- A **Korg Kaossilator Pro+** gets a custom filter that turns notes into positions on its XY pad. X comes from the note and Y from a knob on the keyboard.

*Diagram: MIDI events from the keyboard through the filter chain to two instruments*

On the little screen there's a text-mode (curses) interface, and the four hardware buttons are used to switch modes, and the code itself is based on the filter example from python-rtmidi.

[Source on GitHub](https://github.com/marcinklimek/midiHost).

Source: https://klimek.link/projects/midihost/